Intensively kept pigs pre-disposed to chlamydial associated conjunctivitis

Area of Science:

• Veterinary Microbiology
• Animal Ophthalmology
• Infectious Diseases

Background:

• Ocular chlamydial infections are a concern in swine populations.
• Farming systems may influence pathogen prevalence and disease manifestation.
• Acanthamoebae are investigated as potential vectors for Chlamydia.

Purpose of the Study:

• To investigate ocular Chlamydiaceae infections in pigs from different farming systems.
• To assess co-infections with Acanthamoebae spp. in relation to clinical signs.
• To compare pathogen prevalence between intensive (Germany) and extensive (Switzerland) farming systems.

Main Methods:

• Screening of 181 pigs (102 German, 79 Swiss) using PCR for Chlamydiaceae and Acanthamoebae.
• Utilized a novel Chlamydiaceae-specific intergenic spacer rRNA gene PCR.
• Clinical examination and cytology were performed and compared.

Main Results:

• High prevalence of Chlamydia suis in symptomatic pigs (CH 79%, GER 90%).
• Intensive farming (GER) showed higher C. suis prevalence in asymptomatic pigs (88%) vs. extensive (CH 23%).
• Co-infection of Acanthamoebae and C. suis was associated with severe ocular manifestations in intensively farmed pigs.

Conclusions:

• Intensively managed pigs are predisposed to ocular chlamydial infections and conjunctivitis.
• Chlamydia-like organisms alone or with Acanthamoebae did not correlate with clinical signs.
• Acanthamoebae and C. suis co-infection significantly contributes to severe ocular disease in intensive pig farming.